Spectro-temporal acoustic elements of music interact in an integrated way to modulate emotional responses in pigs.

Music is a complex stimulus, with various spectro-temporal acoustic elements determining one of the most important attributes of music, the ability to elicit emotions. Effects of various musical acoustic elements on emotions in non-human animals have not been studied with an integrated approach. However, this knowledge is important to design music to provide environmental enrichment for non-human species. Thirty-nine instrumental musical pieces were composed and used to determine effects of various acoustic parameters on emotional responses in farm pigs. Video recordings (n = 50) of pigs in the nursery phase (7-9 week old) were gathered and emotional responses induced by stimuli were evaluated with Qualitative Behavioral Assessment (QBA). Non-parametric statistical models (Generalized Additive Models, Decision Trees, Random Forests, and XGBoost) were applied and compared to evaluate relationships between acoustic parameters and pigs' observed emotional responses. We concluded that musical structure affected emotional responses of pigs. The valence of modulated emotions depended on integrated and simultaneous interactions of various spectral and temporal structural components of music that can be readily modified. This new knowledge supports design of musical stimuli to be used as environmental enrichment for non-human animals.

Music modulates emotional responses in growing pigs.

There is a lack of clarity on whether pigs can emotionally respond to musical stimulation and whether that response is related to music structure. Qualitative Behavioral Assessment (QBA) was used to evaluate effects of 16 distinct musical pieces (in terms of harmonic structure) on emotional responses in nursery pigs (n = 30) during four periods: "habituation", "treatments", "breaks" and "final". Data were evaluated using Principal component analysis (PCA). Two principal components (PC) were considered in the analysis: PC1, characterized as a positive emotions index, included the emotional responses content, playful, sociable, and happy, whereas PC2, characterized as a negative emotions index, included fearful, inquisitive, and uneasy with positive loadings, and relaxed and calm with negative loadings. Musical stimulation (treatment) increased (P < 0.01) both emotional indices, compared to other periods and this response was influenced by harmonic characteristics of the music. We concluded that pigs have a wide variety of emotional responses, with different affective states related to the music structure used, providing evidence of its potential use as environmental enrichment for this species.

Adaptive Responses to Thermal Stress in Mammals / Respuestas de adaptación al estrés térmico en mamíferos / Respostas de adaptação ao estresse térmico em mamíferos

The environment animals have to cope with is a combination of natural factors such as temperature. Extreme changes in these factors can alter homeostasis, which can lead to thermal stress. This stress can be due to either high temperatures or low temperatures. Energy transference for thermoregulation in homoeothermic animals occurs through several mechanisms: conduction, convection, radiation and evaporation. When animals are subjected to thermal stress, physiological mechanisms are activated which may include endocrine, neu-roendocrine and behavioral responses. Activation of the neuroendocrine system affects the secretion ofhormones and neurotransmitters which act collectively as response mechanisms that allow them to adapt to stress. Mechanisms which have developed through evolution to allow animals to adapt to high environmental temperatures and to achieve thermo tolerance include physiological and physical changes in order to reduce food intake and metabolic heat production, to increase surface area of skin to dissipate heat, to increase blood flow to take heat from the body core to the skin and extremities to dissipate the heat, to increase numbers and activity of sweat glands, panting, water intake and color adaptation of integument system to reflect heat. Chronic exposure to thermal stress can cause disease, reduce growth, decrease productive and reproductive performance and, in extreme cases, lead to death. This paper aims to briefly explain the physical and physiological responses of mammals to thermal stress, like a tool for biological environment adaptation, emphasizing knowledge gaps and offering some recommendations to stress control for the animal production system.

El ambiente al que los animales tienen que enfrentarse es una combinación de factores naturales. Cambios extremos en estos factores pueden alterar la homeostasis y conducir al estrés térmico. Este puede resultar tanto de temperaturas altas como de temperaturas bajas. Cuando se somete a los animales a estrés térmico, se activan mecanismos fisiológicos que pueden incluir respuestas endocrinas, neuroendocrinas y de comportamiento. Los mecanismos desarrollados a través de la evolución para que los animales se adapten a temperaturas ambientales altas y alcancen termotolerancia incluyen cambios fisiológicos y físicos, a fin de reducir la ingesta de alimentos y la producción del calor metabólico; de aumentar el área superficial de la piel para disipar el calor; de aumentar el flujo de sangre para llevar el calor del núcleo del cuerpo a la piel y las extremidades para disipar el calor, o de aumentar el número y la actividad de las glándulas sudoríparas, el jadeo, la ingesta de agua y la adaptación del color del sistema de tegumento para reflejar el calor. La exposición crónica al estrés térmico puede causar enfermedad, reducir el crecimiento, disminuir el rendimiento productivo y reproductivo y, en casos extremos, llevar a la muerte. El objetivo de este trabajo es explicar las respuestas físicas y fisiológicas de los mamíferos al estrés térmico, como una herramienta para la adaptación al entorno biológico, haciendo hincapié en las lagunas de nuestro conocimiento y ofreciendo algunas recomendaciones para controlar el estrés en el sistema de producción animal.

O ambiente ao que os animais têm que enfrentar-se é uma combinação de fatores naturais. Mudanças extremas nestes fatores podem alterar a homeostase e levar ao estresse térmico. Este pode resultar tanto de temperaturas altas quanto de temperaturas baixas. Quando se submete os animais a estresse térmico, se ativam mecanismos fisiológicos que podem incluir respostas endócrinas, neuroendócrinas e de comportamento. Os mecanismos desenvolvidos através da evolução para que os animais se adaptem a temperaturas ambientais altas e alcancem termo tolerância incluem mudanças fisiológicas e físicas, visando reduzir a ingesta de alimentos e a produção do calor metabólico; de aumentar a área superficial da pele para dissipar o calor; de aumentar o fluxo de sangue para levar o calor do núcleo do corpo à pele e às extremidades para dissipar o calor, ou de aumentar o número e a atividade das glândulas sudoríparas, o arquejo, a ingestão de água e a adaptação da cor do sistema de tegumento para refletir o calor. A exposição crônica ao estresse térmico pode causar doença, reduzir o crescimento, diminuir o rendimento produtivo e reprodutivo e, em casos extremos, levar à morte. O objetivo deste trabalho é explicar as respostas físicas e fisiológicas dos mamíferos ao estresse térmico, como uma ferramenta para a adaptação ao entorno biológico, enfatizando nas lagoas de nosso conhecimento e oferecendo algumas recomendações para controlar o estresse no sistema de produção animal.